[ubuntu-x] evdev touch screen input noise filter

Dan Squires dan at engineeredarts.co.uk
Fri May 16 13:29:54 UTC 2014

Hi there,

In our application we have the misfortune of having to use a capacitive 
kiosk touch-screen that seems to have a horrendous problem with 
electrical noise pickup, to the point where the cursor moves across the 
screen rapidly (oscillates) by upto hundreds of pixels.

Since Ubuntu 11.04 we have been applying a hack to the evdev code to 
reduce this noise to bearable levels by doing some fairly aggressive 
filtering. I'm assuming the supplied windows driver must do something 
similar as I am told there is little if any noise apparent when plugged 
into such a PC.

I am hoping to get a better solution integrated into future 
distributions but do not know where best to apply such a patch that 
would be acceptable.

hopefully somebody can make some suggestions?

Many Thanks

Dan Squires

Engineered Arts Ltd.

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